Question 1

________ Inner cells of the dental sac&#10;A)Dental pulp&#10;B)Predentin&#10;C)Dental sac&#10;D)Enamel&#10;E)Cement

Accepted Answer

The inner cells of the dental sac differentiate into cementoblasts,which produce cement (L.cementum)and deposit it over the dentin of the root.

Question 2

________ Lanugo&#10;A)Tetracyclines&#10;B)Ameloblastic layer&#10;C)Hair follicles&#10;D)Neural crest cells&#10;E)Epithelial root sheath of the developing tooth

Accepted Answer

Lanugo is the soft downy hairs that are first produced by the hair follicles.These hairs are chiefly shed before or right after birth and are replaced by coarser hairs that arise from new hair follicles.

Question 3

________ Fused layers of enamel epithelia&#10;A)Tetracyclines&#10;B)Ameloblastic layer&#10;C)Hair follicles&#10;D)Neural crest cells&#10;E)Epithelial root sheath of the developing tooth

Accepted Answer

The inner and outer enamel epithelia of the enamel organ come together and fuse in the neck region of the tooth,where they form the epithelial root sheath.This sheath grows into the mesenchyme and initiates root formation.

Question 4

________ Derived from the inner enamel epithelium&#10;A)Tetracyclines&#10;B)Ameloblastic layer&#10;C)Hair follicles&#10;D)Neural crest cells&#10;E)Epithelial root sheath of the developing tooth

Accepted Answer

The ameloblastic layer is derived from the inner enamel epithelium of the enamel organ.The ameloblasts produce enamel and deposit it over the dentin.As the enamel increases,the ameloblasts regress toward the outer enamel epithelium.Enamel and dentin formation begins at the tip (cusp)of the tooth and progresses toward the future root.

Question 5

________ Dental lamina&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The dental lamina develops from the oral ectoderm and gives rise to the deciduous and permanent tooth buds.

Question 6

________ Melanocytes&#10;A)Tetracyclines&#10;B)Ameloblastic layer&#10;C)Hair follicles&#10;D)Neural crest cells&#10;E)Epithelial root sheath of the developing tooth

Accepted Answer

Melanocytes differentiate from melanoblasts,which are derived from neural crest cells.Melanoblasts migrate into the dermis during the early fetal period and soon enter the epidermis where they slowly differentiate into melanocytes.These cells produce melanin and distribute it to the epidermal cells after birth.Melanoblasts also migrate into the hair bulbs and differentiate into melanocytes.Melanin is distributed to the hair-forming cells before birth.

Question 7

________ Sebaceous glands&#10;A)Tetracyclines&#10;B)Ameloblastic layer&#10;C)Hair follicles&#10;D)Neural crest cells&#10;E)Epithelial root sheath of the developing tooth

Accepted Answer

Most sebaceous glands arise as buds from the sides of the epithelial root sheaths of hair follicles,late in the second trimester of pregnancy.A few sebaceous glands develop from the epidermis,independently of hair follicles (e.g. ,in the eyelids and labia minora).

Question 8

________ Bud of the permanent tooth&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The tooth buds for the permanent teeth develop from continuations of the dental laminae.They begin to appear at about 10 weeks and lie lingual to the deciduous tooth buds.

Question 9

________ Contains vessels and nerves&#10;A)Dental pulp&#10;B)Predentin&#10;C)Dental sac&#10;D)Enamel&#10;E)Cement

Accepted Answer

The dental pulp derived from the mesenchymal dental papilla of the embryo contains the vessels and nerves of the tooth.

Question 10

________ Periodontal ligament&#10;A)Dental pulp&#10;B)Predentin&#10;C)Dental sac&#10;D)Enamel&#10;E)Cement

Accepted Answer

The periodontal ligament is derived from the dental sac,a capsule-like structure that develops from the mesenchyme surrounding the tooth.

Question 11

________ Derived from the neural plate&#10;A)Tetracyclines&#10;B)Ameloblastic layer&#10;C)Hair follicles&#10;D)Neural crest cells&#10;E)Epithelial root sheath of the developing tooth

Accepted Answer

The answer of ________ Derived from the neural plate&#10;A)Tetracyclines&#10;B)Ameloblastic layer&#10;C)Hair...

Question 12

________ Dental papilla&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The answer of   ________ Dental papilla&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E...

Question 13

________ Ameloblasts&#10;A)Dental pulp&#10;B)Predentin&#10;C)Dental sac&#10;D)Enamel&#10;E)Cement

Accepted Answer

The answer of ________ Ameloblasts&#10;A)Dental pulp&#10;B)Predentin&#10;C)Dental sac&#10;D)Enamel&#10;E)Cement...

Question 14

________ Discoloration of teeth&#10;A)Tetracyclines&#10;B)Ameloblastic layer&#10;C)Hair follicles&#10;D)Neural crest cells&#10;E)Epithelial root sheath of the developing tooth

Accepted Answer

The answer of ________ Discoloration of teeth&#10;A)Tetracyclines&#10;B)Ameloblastic layer&#10;C)Hair follicles&#10;D)Neural crest...

Question 15

________ Odontoblasts&#10;A)Dental pulp&#10;B)Predentin&#10;C)Dental sac&#10;D)Enamel&#10;E)Cement

Accepted Answer

The answer of ________ Odontoblasts&#10;A)Dental pulp&#10;B)Predentin&#10;C)Dental sac&#10;D)Enamel&#10;E)Cement...

Question 16

________ Induction of the odontoblastic layer&#10;A)Tetracyclines&#10;B)Ameloblastic layer&#10;C)Hair follicles&#10;D)Neural crest cells&#10;E)Epithelial root sheath of the developing tooth

Accepted Answer

The answer of ________ Induction of the odontoblastic layer&#10;A)Tetracyclines&#10;B)Ameloblastic layer&#10;C)Hair...

Question 17

________ Inner enamel epithelium&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The answer of   ________ Inner enamel epithelium&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E...

Question 18

________ Dental sac&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The answer of   ________ Dental sac&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E...

Question 19

________ Inner enamel epithelium&#10;A)Dental pulp&#10;B)Predentin&#10;C)Dental sac&#10;D)Enamel&#10;E)Cement

Accepted Answer

The answer of ________ Inner enamel epithelium&#10;A)Dental pulp&#10;B)Predentin&#10;C)Dental sac&#10;D)Enamel&#10;E)Cement...

Question 20

________ Part of the enamel organ&#10;A)A&#10;B)B&#10;C)C&#10;D)D&#10;E)E

Accepted Answer

The answer of   ________ Part of the enamel...

Deck 17: Integumentary System